function $(id) {
    if(typeof(id) != 'undefined'){
        var a = id.toString().split(':');
        if(a.length==2)
            return document.getElementById(a[0]).getElementsByTagName(a[1]);
        else 
            return document.getElementById(id);
    };
};

function nv_click() {
    var nb = $('numbox');
    nb.style.display = nb.style.display=='block' ? 'none' : 'block';
};
